CRII: RI: Responsive Movement Primitives for Soft Robot Control

Case Western Reserve University, Cleveland OH

Investigators

Abstract

Controlling many actuators based on many sensors is important for developing smart robots that mimic human abilities, mobile robots that go places humans cannot go, and for soft robots in general, which may be wearable, swallowable, or safe for other delicate environments. Animals and humans can easily and deftly respond to touch anywhere on their skin. As a result, for example, a human can pick up a handful of objects in the dark or a worm can feel its way through an underground burrow. However, The approaches that work to control sensors and actuators on robots may not scale up for more degrees of freedom and sensors. Soft robots are especially imprecise and often designed for contact, which means more robust, intelligent control is needed. Separating the control problem into simpler subparts called primitives can make controller design and adaptation easier. Such primitives seem to be fundamental to biological nervous systems. The goal of this project is to establish a format for primitives that are responsive, specifically to local contact sensing. These primitives will be applied to two common types of robot problems: manipulation and locomotion. The project is a step toward enabling more life-like performance in robots and better understanding of the complexity of biological intelligence. This project will build on the widely used Dynamic Movement Primitives (DMP) framework by replacing the stable equilibria and limit cycles with connected saddle equilibria. The saddle equilibria will enable the timing of the system states to vary with sensory input, resulting in Responsive Movement Primitives (RMP). We will explore two design approaches to RMP: converting directly from DMP and extending a previous saddle-based controller to additional degrees of freedom. The first approach will be implemented for a hyper-redundant grasping problem because this relates to published DMP benchmarks. This study has the potential to help robots pick up multiple objects in a single grasp. The second approach will be implemented for peristaltic worm-like locomotion problem and leverages the investigator?s prior research. This study will help engineers better understand how soft body locomotion can be used to access constrained spaces with potential future application in medicine, infrastructure access, and search and rescue. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.